Staging with 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) for nonseminomatous germ cell tumor (NSGCT): The Peter MacCallum Cancer Centre experience

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Background: We retrospectively evaluated our single institution experience using FDG-PET as part of initial assessment of stage I/II NSGCT. Previous studies by de Wit et al and the TE22 trial concluded that there was a very limited role for PET staging in NSGCT. Despite these results, PET continues to be utilised in our center. Methods: With local ethics approval, the PET center database at Peter MacCallum Cancer Centre (PMCC) was used to identify a series of 26 patients with NSGCT who underwent FDG-PET as part of staging investigations between 1998 and 2008. Demographic and clinical information was collected using electronic and paper medical records. Histological samples were reviewed if additional information was required. Results: Lymphovascular invasion (LVI) was present in 10 (38%) of orchiectomy specimens. 15 patients had stage I disease on both CT and PET. PET upstaged 7 patients from stage I to stage II disease, and all upstaged patients received systemic chemotherapy (3 cycles BEP). 1 patient with stage I disease on PET and CT received adjuvant chemotherapy (2 cycles EP). 3 patients with LVI and stage 1 disease on CT and PET underwent surveillance. With median follow-up of 33 months (range 1–94), all patients were alive without disease recurrence, although 1 patient was treated for a second primary NSGCT. Conclusions: Using PET images, we were able to identify patients with low volume metastatic disease and achieve 100% relapse-free survival rates. Despite the small sample size, these results are promising and are better than expected based on published data. This might be explained by the quality of the PET imaging, including attenuation correction and combined CT/PET for enhanced sensitivity interpreting retroperitoneal disease. Further evaluation of PET is warranted, particularly in patients with equivocal CTs or with the high-risk feature of LVI. [Table: see text]

No significant financial relationships to disclose.

Laser-assisted microdissection: a new tool for aquatic molecular parasitology

Laser-assisted microdissection (LMD) has been developed to isolate distinct cell populations from heterogeneous tissue sections, cytological preparations, or live cell samples. Downstream applications typically include gene expression studies using real-time PCR and array platforms, diagnostic PCR, and protein expression studies. LMD techniques are now commonplace in mainstream biological research and clearly have suitable applications in the field of aquatic pathology and parasitology. The present study used LMD to isolate 2 dinoflagellate parasites (Hematodinium spp.) from formalin-fixed paraffin-embedded tissue sections from 2 crustacean hosts, Cancer pagurus and Portunus trituberculatus. DNA was isolated from LMD parasite preparations, and partial regions (up to 300 bp) of the small subunit and the first internal transcribed spacer region of the rRNA gene complex from the Hematodinium spp. were PCR amplified using diagnostic primers. The amplification products were sequenced to confirm the identity of the targeted regions. The techniques, applications, and limitations of LMD to address questions in aquatic molecular pathology and parasitology are discussed.

Utility of 18-fluorodeoxyglucose positron emission tomography (FDG-PET) in the staging, radiotherapy planning and prognostication of anal cancer

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Background: Accurate inguinal and pelvic nodal staging in anal cancer is important for prognosis and planning of (chemo)radiation fields. There is strong evidence for the impact of FDG-PET in staging and management of cancer, with early reports of an increasing role in outcome prognostication for a number of tumours. We aimed to determine the impact of FDG-PET on the nodal staging, radiotherapy planning and prognostication of patients with primary anal cancer. Methods: Sixty-two consecutive patients with anal cancer referred to a single tertiary oncology centre between August 1997 and November 2005 were staged with conventional imaging (CIm), computed tomography, magnetic resonance imaging and chest x-ray and by FDG-PET. The stage determined by CIm and the proposed management plan was prospectively recorded and changes in stage and management as a result of FDG-PET assessed. Patients were treated using uniform radiotherapy technique and dose. The accuracy of changes and prognostication of FDG-PET was validated by subsequent clinical follow-up. Kaplan-Meier survival analysis was used to assess survival for the cohort and by FDG-PET and CIm stage. Results: The TNM stage group was changed in 23% (14/62) as a result of FDG-PET (15% up-staged, 8% down-staged). Fourteen percent of T1 patients (3/22), 42% of T2 patients (10/24) and 38% of T3–4 patients (6/16), assessed using CIm, had a change in their N or M stage following FDG-PET. Sensitivity for nodal disease by FDG-PET and CIm was 92% and 72% respectively. The staging FDG-PET scan altered management intent in 3% (2/62), and altered radiotherapy fields in 13% (8/62). Estimated 5 year overall survival and progression free survival (PFS) for the cohort was 77.3% (95% CI 55.3%-90.4%) and 72.2% (95% CI 51.5%-86.4%) respectively. Estimated 5 year PFS for FDG-PET and CIm staged N2–3 disease was 70% (95% CI 42.8%-87.9%) and 55.3% (95% CI 23.3%-83.4%) respectively. Conclusions: FDG-PET shows increased sensitivity over CIm for staging nodal disease in anal cancer and changes treatment intent or radiotherapy fields in a significant proportion of patients. Improved 5 year PFS for FDG-PET staged N2–3 disease could be consistent with more accurate nodal staging and radiotherapy targeting.

No significant financial relationships to disclose.

Measurements of the generalized electric and magnetic polarizabilities of the proton at low Q2 using the virtual-compton-scattering reaction

The mean square polarizability radii of the proton have been measured for the first time in a virtual-Compton-scattering experiment performed at the MIT-Bates out-of-plane scattering facility. Response functions and polarizabilities obtained from a dispersion analysis of the data at Q2 = 0.057 GeV2/c2 are in agreement with O(p3) heavy baryon chiral perturbation theory. The data support the dominance of mesonic effects in the polarizabilities.